Agronomic and Environmental Effects of Phosphorus Fertilizer Application Methods

As farm size increases on the Canadian prairies, improving operational efficiency is important for growers. While seed row placement is generally considered the most effective phosphorus (P) placement method for small grains, there are few recent studies comparing agronomic effectiveness of different P fertilizer placement strategies on the prairies in modern no-till cropping systems and environmental considerations must be made in tandem as snowmelt runoff is an important exporter of P in the prairies. The objective of this research was to evaluate the effect of application strategy of monoammonium phosphate fertilizer (MAP) on crop response and P export in a simulated snowmelt runoff and leachate water over two consecutive years of application. The field study was conducted on a typical no-till field with good inherent P fertility located in the Brown soil zone in south-central Saskatchewan near Central Butte. Three in-soil MAP placement treatments (seed placed, deep banded, and broadcast with incorporation) at 20 kg P2O5 ha-1 and three broadcast (20, 40, and 80 kg P2O5 ha-1) treatments were applied each spring along with a control without P fertilizer in an RCBD set up on two sites in the field. Wheat (Triticum aestivum var. Waskada) was seeded in 2015 and canola (Brassica napus var. LL 250) was seeded in 2016. Treatment was not significant in 2015. In 2016, treatment was significant and uptake of P by canola was significantly higher in the 80 kg P2O5 ha-1 broadcast treatment than in other treatments. In the fall of 2016 after harvest, soil monoliths were collected and used to assess vertical and horizontal distribution patterns of soil available P in the surface soil profile. Mapping of residual P indicated zones of depletion below 5-cm in the in-soil P placement treatments, likely due to stimulated root growth, while the broadcast treatment revealed minor surface loading of P. Only the broadcast application at the high rate (80 kg P2O5 ha-1) showed enhanced export in the simulated snowmelt runoff and leachate, and a higher proportion of the P in snowmelt runoff was in the dissolved reactive fraction in this treatment. Assessment of P forms in the runoff using NMR spectroscopy suggested that higher application rates may also be associated with increased microbial activity and production of organic P forms in the soil. Due to high inherent fertility, lower rates of P would be advisable in these soils as crop response to fertilization was limited and high rates of broadcast MAP substantially increased P export in water

Variations in solar wind fractionation as seen by ACE/SWICS over a solar cycle and the implications for Genesis Mission results

We use ACE/SWICS elemental composition data to compare the variations in solar wind fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009) and the period in which the Genesis spacecraft was collecting solar wind (late 2001 - early 2004). We differentiate our analysis in terms of solar wind regimes (i.e. originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-FIP ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative to magnesium, the other low-FIP elements are measurably fractionated, but the degree of fractionation does not vary significantly over the solar cycle. For the high-FIP ions, variation in fractionation over the solar cycle is significant: greatest for Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance ratios are examined as a function of solar wind speed, we find a strong correlation, with the remarkable observation that the degree of fractionation follows a mass-dependent trend. We discuss the implications for correcting the Genesis sample return results to photospheric abundances.Comment: Accepted for publication in Ap

Cell cycle-dependent phosphorylation of Theileria annulata schizont surface proteins

The invasion of Theileria sporozoites into bovine leukocytes is rapidly followed by the destruction of the surrounding host cell membrane, allowing the parasite to establish its niche within the host cell cytoplasm. Theileria infection induces host cell transformation, characterised by increased host cell proliferation and invasiveness, and the activation of anti-apoptotic genes. This process is strictly dependent on the presence of a viable parasite. Several host cell kinases, including PI3-K, JNK, CK2 and Src-family kinases, are constitutively activated in Theileria-infected cells and contribute to the transformed phenotype. Although a number of host cell molecules, including IkB kinase and polo-like kinase 1 (Plk1), are recruited to the schizont surface, very little is known about the schizont molecules involved in host-parasite interactions. In this study we used immunofluorescence to detect phosphorylated threonine (p-Thr), serine (p-Ser) and threonine-proline (p-Thr-Pro) epitopes on the schizont during host cell cycle progression, revealing extensive schizont phosphorylation during host cell interphase. Furthermore, we established a quick protocol to isolate schizonts from infected macrophages following synchronisation in S-phase or mitosis, and used mass spectrometry to detect phosphorylated schizont proteins. In total, 65 phosphorylated Theileria proteins were detected, 15 of which are potentially secreted or expressed on the surface of the schizont and thus may be targets for host cell kinases. In particular, we describe the cell cycle-dependent phosphorylation of two T. annulata surface proteins, TaSP and p104, both of which are highly phosphorylated during host cell S-phase. TaSP and p104 are involved in mediating interactions between the parasite and the host cell cytoskeleton, which is crucial for the persistence of the parasite within the dividing host cell and the maintenance of the transformed state

The association of statin use after cancer diagnosis with survival in pancreatic cancer patients: a SEER-medicare analysis.

BackgroundPancreatic cancer has poor prognosis and existing interventions provide a modest benefit. Statin has anti-cancer properties that might enhance survival in pancreatic cancer patients. We sought to determine whether statin treatment after cancer diagnosis is associated with longer survival in those with pancreatic ductal adenocarcinoma (PDAC).MethodsWe analyzed data on 7813 elderly patients with PDAC using the linked Surveillance, Epidemiology, and End Results (SEER) - Medicare claims files. Information on the type, intensity and duration of statin use after cancer diagnosis was extracted from Medicare Part D. We treated statin as a time-dependent variable in a Cox regression model to determine the association with overall survival adjusting for follow-up, age, sex, race, neighborhood income, stage, grade, tumor size, pancreatectomy, chemotherapy, radiation, obesity, dyslipidemia, diabetes, chronic pancreatitis and chronic obstructive pulmonary disease (COPD).ResultsOverall, statin use after cancer diagnosis was not significantly associated with survival when all PDAC patients were considered (HR = 0.94, 95%CI 0.89, 1.01). However, statin use after cancer diagnosis was associated with a 21% reduced hazard of death (Hazard ratio = 0.79, 95% confidence interval (CI) 0.67, 0.93) in those with grade I or II PDAC and to a similar extent in those who had undergone a pancreatectomy, in those with chronic pancreatitis and in those who had not been treated with statin prior to cancer diagnosis.ConclusionsWe found that statin treatment after cancer diagnosis is associated with enhanced survival in patients with low-grade, resectable PDAC

Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes

A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum intensities and center-limb behavior constrained the temperature profile of the deep photosphere, while CO center-limb behavior defined the thermal structure at higher altitudes. The oxygen abundance was self consistently determined from weak CO absorptions. Our analysis was meant to complement recent studies based on 3-D convection models which, among other things, have revised the historical solar oxygen (and carbon) abundance downward by a factor of nearly two; although in fact our conclusions do not support such a revision. Based on various considerations, an oxygen abundance of 700+/-100 ppm (parts per million relative to hydrogen) is recommended; the large uncertainty reflects the model sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O, and 18O.Comment: 90 pages, 19 figures (some with parts "a", "b", etc.); to be published in the Astrophysical Journal Supplement

Dust Removal on Mars Using Laser-Induced Breakdown Spectroscopy

Dust coatings on the surface of Mars complicate and, if sufficiently thick, mask the spectral characteristics and compositional determination of underlying material from in situ and remote sensing instrumentation. The Laser-Induced Breakdown Spectroscopy (LIBS) portion of the Chemistry & Camera (ChemCam) instrument, aboard the Mars Science Laboratory (MSL) rover, will be the first active remote sensing technique deployed on Mars able to remove dust. ChemCam utilizes a 5 ns pulsed 1067 nm high-powered laser focused to less than 400 m diameter on targets at distances up to 7 m [1,2]. With multiple laser pulses, dust and weathering coatings can be remotely analyzed and potentially removed using this technique [2,3]. A typical LIBS measurement during MSL surface operations is planned to consist of 50 laser pulses at ~14 mJ, with the first 5 to 10 pulses used to analyze as well as remove any surface coating. Additionally, ChemCam's Remote Micro-Imager (RMI) is capable of resolving 200 m details at a distance of 2 m, or 1 mm at 10 m [1,4]. In this study, we report on initial laboratory experiments conducted to characterize the removal of dust coatings using similar LIBS parameters as ChemCam under Mars-like conditions. These experiments serve to better understand the removal of surface dust using LIBS and to facilitate the analysis of ChemCam LIBS spectral data and RMI images

Light and heavy transfer products in Xe 136 + U 238 multinucleon transfer reactions

A. Vogt et al.; 12 pags.; 14 figs.; PACS number(s): 24.10.−i, 25.70.Hi, 29.30.Aj, 29.40.Gx© 2015 American Physical Society. ©2015 American Physical Society. Background: Multinucleon transfer reactions (MNT) are a competitive tool to populate exotic neutron-rich nuclei in a wide region of nuclei, where other production methods have severe limitations or cannot be used at all. Purpose: Experimental information on the yields of MNT reactions in comparison with theoretical calculations are necessary to make predictions for the production of neutron-rich heavy nuclei. It is crucial to determine the fraction of MNT reaction products which are surviving neutron emission or fission at the high excitation energy after the nucleon exchange. Method: Multinucleon transfer reactions in Xe136+U238 have been measured in a high-resolution γ-ray/particle coincidence experiment. The large solid-angle magnetic spectrometer PRISMA coupled to the high-resolution Advanced Gamma Tracking Array (AGATA) has been employed. Beamlike reaction products after multinucleon transfer in the Xe region were identified and selected with the PRISMA spectrometer. Coincident particles were tagged by multichannel plate detectors placed at the grazing angle of the targetlike recoils inside the scattering chamber. Results: Mass yields have been extracted and compared with calculations based on the grazing model for MNT reactions. Kinematic coincidences between the binary reaction products, i.e., beamlike and targetlike nuclei, were exploited to obtain population yields for nuclei in the actinide region and compared to x-ray yields measured by AGATA. Conclusions: No sizable yield of actinide nuclei beyond Z=93 is found to perform nuclear structure investigations. In-beam γ-ray spectroscopy is feasible for few-neutron transfer channels in U and the -2p channel populating Th isotopes.The research leading to these results has received funding from the German Bundesministerium fur Bildung ¨ und Forschung (BMBF) under Contract No. 05P12PKFNE TP4, the European Union Seventh Framework Programme (FP7/2007-2013) under Grant No. 262010-ENSAR, and the Spanish Ministerio de Ciencia e Innovacion under Contract ´ No. FPA2011-29854-C04. A.V. thanks the Bonn-Cologne Graduate School of Physics and Astronomy (BCGS) for financial support. One of the authors (A. Gadea) was supported by MINECO, Spain, under Grants No. FPA2011-29854-C04 and No. FPA2014-57196-C5, Generalitat Valenciana, Spain, under Grant No. PROMETEOII/2014/019, and EU under the FEDER program.Peer Reviewe

Variations in Solar Wind Fractionation as Seen by \u3ci\u3eACE\u3c/i\u3e/SWICS and the Implications for \u3ci\u3eGenesis\u3c/i\u3e Mission Results

We use Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer (SWICS) elemental composition data to compare the variations in solar wind (SW) fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009), and the period in which the Genesis spacecraft was collecting SW (late 2001-early 2004). We differentiate our analysis in terms in SW regimes (i.e., originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-first ionization potential (low-FIP) ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative to magnesium, the other low-FIP elements are measurably fractionated, but the degree of fractionation does not vary significantly over the solar cycle. For the high-FIP ions, variations in fractionation over the solar cycle is significant: greatest for Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance ratios are examined as a function of SW speed, we find a strong correlation, with the remarkable observation that the degrees of fractionation follows a mass-dependent trend. We discuss the implications for correcting the Genesis sample return results to photospheric abundances

In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. However, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. The new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, however, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites